Stools are a normal process of eliminating body waste. Stools consist of indigestible fat, food residue, bacteria, and a large percentage of water. Different stool colors can be due to different causes but mostly due to the food we eat.

What Is the Normal Color of the Poop?

The healthy stool is brown. Stool color is influenced by the diet and the amount of bile. Bile is a yellow-green fluid produced by the liver. It helps in the digestion of fats. As the bile travels through the digestive system, it goes through chemical changes by the enzymes and turns brown.

What Is the Cause of Green Poop?

The poop can appear green in the following conditions:

Diarrhea: When the food moves through the large intestine quickly, the bile does not break down completely and results in green color.
Foods: The chlorophyll in the plants gives the green color. Dietary causes like green leafy vegetables, taking a course of antibiotics, green food coloring present in flavored drinks, ice pops, and iron supplements can cause green poop.

Foods and drinks that can cause green poop include:

Blueberries, purple, or blue fruits and vegetables.
Green fruits like green apples and avocado.
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Herbs such as basils and parsley.
Powdered green tea.
Hemp seeds.
Pistachios.
Broccoli.

Medical Procedures: In cases like bone marrow transplant, if the body rejects the transplant, a person may develop graft-versus-host disease. This condition results in diarrhea and green stools.
Infections: Green poop is caused by a bacterial infection (Salmonella or E.coli), viral infection (Norovirus), or parasitic infection (Giardia).
Antibiotics: Antibiotics can sometimes alter the bacterial flora in the gut and change the color of the poop. Some antibiotics can cause diarrhea in which the bile does not break down completely and passes fast through the intestine, giving a green color to the poop.
Removal of the Gallbladder: Recent gallbladder removal due to any gallbladder disease can cause green poop because more bile is released into the digestive tract, leading to greenish diarrhea.
Gastrointestinal Conditions: In inflammatory bowel diseases such as Crohn's disease, bile moves through the intestine too quickly, resulting in green poop. Celiac disease, due to an immune response to eating gluten, causes diarrhea resulting in green poop. Irritable bowel syndrome, ulcerative colitis, and laxative overuse can also cause green poop since all these conditions cause bile to move fast through the intestine.
Anal Fissures: Anal fissures caused due to chronic diarrhea can cause green stool.
Food Poisoning: Food allergies and food poisoning can cause gastroenteritis resulting in diarrhea with green poop.
Medications: Certain medications like non-steroidal anti-inflammatory drugs (Indomethacin) and birth control shots, Depo-Provera can cause green poop.

Can Green Poop Occur in Pregnant Women?

Green stool can occur during the early weeks or in the third trimester of pregnancy. Women may get green stools because pregnant women are mostly prescribed prenatal vitamins and iron supplements. Some women get loose green stools as the food moves fast through the intestines.

What Does Green Poop in Babies and Toddlers Indicate?

A newborn's first poop will be green in color, which is called meconium. It usually stops after three days. If a breastfed baby's poop is green in color, it is due to the mother's diet. A mother's diet containing green vegetables or green or purple coloring may cause green poop in a breastfed baby. Green poop in breastfed babies may also indicate that the baby does not get enough hindmilk (milk higher in fat) and gets too much low-calorie, low-fat dairy.

Is Green Poop a Sign of Cancer?

Green stools are usually not a sign of cancer. Cancer is associated with black or tarry stools. If the green poop is accompanied by some other symptoms like chronic diarrhea and vomiting, this can indicate a serious medical condition.

What Are the Other Color Changes in the Stool?

Some of the color changes in the stool and their causes include:

Yellow Stool: Due to excess fat in the stool due to malabsorption. Celiac disease, which occurs due to a response to eating gluten, may also cause yellow stool.
Light-Colored (Gray or White) Stool: Indicates lack of bile in stool as in bile duct obstruction. It may also be due to medications like large doses of bismuth subsalicylate and some antidiarrheal drugs.
Black Stool: Bleeding in the stomach. Iron supplements can cause black stools.
Bright Red Stool: Bleeding in the large intestine or rectum (lower gastrointestinal tract). Red food coloring, beetroots, and red-colored drinks may also cause red stool.
Orange Stool: Consuming more orange-colored foods containing the pigment beta carotene.

What Is the Diagnosis of Green Stools?

A complete diet history, frequency of green stools, other associated symptoms, past medical history, medications, and supplements you are taking are noted. If there is an underlying medical condition, specific blood or imaging tests and stool tests are done to rule out the cause.

How Can We Prevent Green Poop?

Dietary changes are the most common cause of green stool. A diet diary and stool changes can identify what food is causing the green stool. If the diet is causing green poop, avoiding foods containing green pigments can prevent green poop.

Foods to be avoided include:

Green leafy vegetables.
Broccoli.
Green apples and avocados.
Blueberries and other blue fruits.
Green-colored drinks.

Review your medication, like iron supplements, birth control pills, etc. If the green poop is due to an underlying condition like celiac disease, avoiding gluten may help prevent green poop. Green stool is also caused by diarrhea which mostly resolves with good hydration and rest.

Conclusion:

Green stool is common at any age. One or two stools with green color do not indicate any serious problem. It is mostly due to vegetables and food supplements. Long-lasting green stool accompanied by other symptoms may indicate some underlying condition and to be immediately evaluated and treated.